Data updated: May 26, 2026
FEMARA (letrozole)
Aromatase Inhibitors
Oncology
Approved 1997-07-25
FEMARA is indicated for the treatment of Breast Cancer.
How FEMARA Works
Letrozole is a nonsteroidal competitive inhibitor of the aromatase enzyme. In postmenopausal women, estrogen is primarily produced by the aromatase enzyme converting adrenal androgens into estrone and estradiol. By blocking this conversion, Femara significantly reduces systemic estrogen levels, thereby inhibiting the growth of tumors that depend on estrogen for progression. The drug is highly selective and does not significantly affect the synthesis of adrenal corticosteroids (mineralocorticoids or glucocorticoids).
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Indications
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Phase 3 Trials
2
Priority Reviews
28
Years on Market
Details
- Status
- Prescription
- First Approved
- 1997-07-25
- Routes
- ORAL
- Dosage Forms
- TABLET
FEMARA Approval History
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Original
New Indication
New Form
Label Update
27 FDA actions from 1997 to 2024 · 7 indication expansions
Oct 2016 SUPPL
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Dec 2015 SUPPL
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Jul 2013 SUPPL
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Jan 2002 SUPPL
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Feb 2001 SUPPL
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May 2000 SUPPL
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Apr 1999 SUPPL
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Mar 1999 SUPPL
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Jul 1997 ORIGINAL
New Drug
What FEMARA Treats
1 indicationsFEMARA is approved for 1 conditions since its original approval in 1997. These indications span multiple therapeutic areas including oncology, immunology, and more.
- Breast Cancer
Source: FDA Label
FEMARA Competitive Set
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Indication competitors
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What's emerging in FEMARA's indications
See all emerging drugs →Phase 3 candidates targeting molecules with no FDA-approved drug, in indications FEMARA treats. First-in-class if their pivotal trials read out positive.
Drugs Similar to FEMARA
3 of 20FDA-approved drugs for similar conditions. Compare mechanisms and indications to understand treatment alternatives.
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Clinical Trial Registry
257 trials| Trial | Sponsor ID | Phase | Status | Title |
|---|---|---|---|---|
| NCT07391774 | NCI-2026-00634 NCI-2026-00634, EA1242 | Ph 3 | not yet recruiting | Testing Whether Hormone Therapy With Ribociclib is as Effective as Chemotherapy Followed by Hormone Therapy With Ribociclib for the Treatment of High Anatomic Stage Breast Cancer With Low Recurrence Risk, The RxFINE-Low Trial |
| NCT06979596 | 5684-015 2024-519563-18-00, U1111-1315-5430 | Ph 2 | recruiting | A Study of MK-5684 in People With Certain Solid Tumors (MK-5684-015/OMAHA-015) |
| NCT07288359 | CGVV858A12101 2025-521911-38 | Ph 1, Ph 2 | recruiting | Study of GVV858 as a Single Agent or in Combination With Endocrine Therapy in Patients With HR+/HER2- Breast Cancer and Other Advanced Solid Tumors |
| NCT06075953 | RECAST-DCIS | Ph 2 | recruiting | DCIS: RECAST Trial Ductal Carcinoma In Situ: Re-Evaluating Conditions for Active Surveillance Suitability as Treatment |
| NCT05827081 Adjuvant WIDER | CLEE011O12001 2022-503001-38-00 | Ph 3 | recruiting | Phase IIIb Study of Ribociclib + ET in Early Breast Cancer |
| NCT06671912 LoTam | A012301 NCI-2024-06672 | Ph 3 | suspended | Testing Low Dose Tamoxifen for Invasive Breast Cancer, the (LoTam) Trial |
| NCT05774951 CAMBRIA-1 | D8531C00002 2022-501024-20-00 | Ph 3 | recruiting | A Study of Camizestrant in ER+/HER2- Early Breast Cancer After at Least 2 Years of Standard Adjuvant Endocrine Therapy |
| NCT07570966 | CERW316A12101 2025-521913-16 | Ph 1, Ph 2 | not yet recruiting | Study of ERW316 as a Single Agent or in Combination With Endocrine Therapy in Patients With HR+/HER2- Breast Cancer and Other Advanced Solid Tumors |
| NCT03179904 results posted | MC1633 W81XWH-16-1-0269, W81XWH-16-1-0268 | Ph 2 | active not recruiting | TVB-2640 and Trastuzumab With Paclitaxel or Endocrine Therapy for Treatment of HER2 Positive Metastatic Breast Cancer |
| NCT05872204 ALEPRO | S66468 | Ph 2 | recruiting | Abemaciclib and Letrozole in Patients With Estrogen Receptor-positive Rare Ovarian Cancer |
| NCT01272037 results posted | NCI-2011-02623 NCI-2011-02623, S12-03603 | Ph 3 | active not recruiting | Tamoxifen Citrate, Letrozole, Anastrozole, or Exemestane With or Without Chemotherapy in Treating Patients With Invasive RxPONDER Breast Cancer |
| NCT06790693 INAVO123 | WO45654 2024-516162-11-00 | Ph 3 | recruiting | A Study Evaluating the Efficacy and Safety of Inavolisib Plus CDK4/6 Inhibitor and Letrozole vs Placebo + CDK4/6i and Letrozole in Participants With Endocrine-Sensitive PIK3CA-Mutated, Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer |
| NCT06998407 AVZO-023-1001 | AVZO-023-1001 | Ph 1, Ph 2 | recruiting | ORION-1: Study of AVZO-023 as a Single Agent and in Combination With AVZO-021, and/or Endocrine Therapy in Advanced Solid Tumors |
| NCT01068249 results posted | 2009-0059 NCI-2011-03639 | Ph 2 | active not recruiting | Letrozole and RAD001 With Advanced or Recurrent Endometrial Cancer |
| NCT03633331 results posted | A171601 NCI-2017-01596 | Ph 2 | completed | Palbociclib and Letrozole or Fulvestrant in Treating Patients With Estrogen Receptor Positive, HER2 Negative Metastatic Breast Cancer |
| NCT07174336 | 27726 J6M-MC-JSGD, 2025-522791-92-00 | Ph 3 | recruiting | A Study of Tersolisib (LY4064809/STX-478) With Other Anti-Cancer Treatments in Participants With Advanced Breast Cancer With a Genetic Change (PIK3CA) |
| NCT06630325 results posted | STUDY00026643 NCI-2024-07664, STUDY00026643 | Ph 2 | terminated | A Precision Medicine Approach (SMMART-ACT) for the Treatment of Patients With Advanced Sarcoma, Prostate, Breast, Ovarian or Pancreatic Cancer |
| NCT07054190 | BO45853 2024-518811-20-00 | Ph 2 | recruiting | A Study to Test Inavolisib Treatments in Participants With Early-Stage, PIK3CA-Mutated Breast Cancer |
| NCT07492641 KANDELA-302 | BGB-43395-302 2025-523960-19-00 | Ph 3 | not yet recruiting | BGB-43395 Plus Letrozole Versus CDK4/6i Plus Letrozole for Patients With Advanced or Metastatic HR+/HER2- Breast Cancer Who Have Not Received Prior Treatment for Advanced or Metastatic Disease |
| NCT06492616 ELEGANT | STML-ELA-0422 2024-515445-42-00 | Ph 3 | recruiting | A Study of Elacestrant Versus Standard Endocrine Therapy in Women and Men With ER+,HER2-, Early Breast Cancer With High Risk of Recurrence |
| NCT06394804 CHAMELEON | 24-014 | Ph 2 | recruiting | A Study of Avutometinib, Defactinib, and Letrozole in People With Low-Grade Serous Ovarian Cancer |
| NCT05768139 PIKALO-1 | 27691 2023-504807-94-00, 2023-000442-41 | Ph 1, Ph 2 | recruiting | First-in-Human Study of Tersolisib (STX-478) as Monotherapy and in Combination With Other Antineoplastic Agents in Participants With Advanced Solid Tumors |
| NCT04964934 SERENA-6 | D8534C00001 2023-503990-39-00, 2021-000546-17 | Ph 3 | active not recruiting | Phase III Study to Assess AZD9833+ CDK4/6 Inhibitor in HR+/HER2-MBC With Detectable ESR1m Before Progression (SERENA-6) |
| NCT06179303 | RG1122019 NCI-2022-06409, FHIRB0020029 | Ph 2 | recruiting | Functional Imaging in Prediction of Response to Abemaciclib for Advanced Hormone Receptor-Positive, HER2-Negative Breast Cancer |
| NCT07085767 OPERA-02 | OP-1250-302 OPERA-02 | Ph 3 | recruiting | Palazestrant in Combination With Ribociclib for the First-line Treatment of ER+/HER2- Advanced Breast Cancer |
| NCT04606446 KAT6 | C4551001 NCT04606446 | Ph 2 | recruiting | Study of PF-07248144 in Advanced or Metastatic Solid Tumors |
| NCT06120283 | BGB-43395-101 2023-506888-34-00, CTR20243370 | Ph 1 | recruiting | BGB-43395 Alone or as Part of Combination Therapies in Participants With Breast Cancer and Other Advanced Solid Tumors |
| NCT03625531 | PPCOSAct | Ph 3 | completed | A Trial of Personalized Acupuncture, Fixed Acupuncture, Letrozole and Placebo on Live Birth in Women With PCOS |
| NCT01553903 OXYTAM | 11 SEIN 09 | Ph 4 | completed | Feasibility Study for the Determination of Oxysterols in Patients With Breast Cancer Receiving Hormonal Therapy With Tamoxifen or Not |
| NCT06380751 EvoPAR-BR01 | D9722C00001 | Ph 3 | recruiting | Saruparib (AZD5305) Plus Camizestrant Compared With CDK4/6 Inhibitor Plus Endocrine Therapy or Plus Camizestrant in HR-Positive, HER2-Negative (IHC 0, 1+, 2+/ ISH Non-amplified), BRCA1, BRCA2, or PALB2m Advanced Breast Cancer |
| NCT05467891 RaPhLRR | HCRN BRE20-468 | Ph 2 | recruiting | Ribociclib And Endocrine Treatment of Physician's Choice for Locoregional Recurrent, Resected Hormone Receptor Positive HER2 Negative Breast Cancer |
| NCT05304273 | G&O/CNMC-118 dt29.12.2021 | Ph 3 | completed | Comparison Between Letrozole and Mifepristone in Medical Termination of First Trimester Miscarriages |
| NCT06072781 RAMP 301 | VS-6766-301 GOG-3097, ENGOT-ov81 | Ph 3 | recruiting | A Study of Avutometinib (VS-6766) + Defactinib (VS-6063) in Recurrent Low-Grade Serous Ovarian Cancer |
| NCT07492394 | OBU-BC-II-278 | Ph 2 | recruiting | Dalpiciclib With or Without Entinostat and Letrozole in HR+/HER2- Early Breast Cancer |
| NCT05514054 EMBER-4 | 18459 J2J-MC-JZLH, 2022-501007-28 | Ph 3 | active not recruiting | A Study of Imlunestrant Versus Standard Endocrine Therapy in Participants With Early Breast Cancer |
| NCT05161195 | CLEE011A2412B 2024-514891-41-00 | Ph 4 | active not recruiting | Roll-over Study to Allow Continued Access to Ribociclib |
| NCT04486352 EndoMAP | AFT-50 | Ph 1, Ph 2 | recruiting | A Study of Targeted Agents for Patients With Recurrent or Persistent Endometrial Cancer |
| NCT01872260 | CLEE011X2107 2023-509511-84-00 | Ph 1, Ph 2 | active not recruiting | Study of LEE011, BYL719 and Letrozole in Advanced ER+ Breast Cancer |
| NCT05649956 | GOG-3088 | Ph 2 | recruiting | Letrozole in Uterine Leiomyosarcoma |
| NCT04095364 | NRG-GY019 NCI-2019-01460, NRG-GY019 | Ph 3 | active not recruiting | Letrozole With or Without Paclitaxel and Carboplatin in Treating Patients With Stage II-IV Ovarian, Fallopian Tube, or Primary Peritoneal Cancer |
| NCT06650748 NeoMARS | OBU-BC-II-164 | Ph 2 | enrolling by invitation | Multigene Risk Score Combined With Ki-67 Dynamic Assessment in Stratified Neoadjuvant Endocrine Therapy Treatment With or Without CDK4/6 Inhibitors in HR+/HER2- Breast Cancer |
| NCT00893061 MNEMOSYNE | MNEMOSYNE-0712 2008-003620-32 | Ph 3 | completed | Letrozole, Anastrozole, Exemestane, or Tamoxifen Citrate in Treating Postmenopausal Women With Breast Cancer |
| NCT03424005 Morpheus-panBC | CO40115 2017-002038-21, 2023-503629-20-00 | Ph 1, Ph 2 | recruiting | A Study Evaluating the Efficacy and Safety of Multiple Treatment Combinations in Patients With Metastatic or Locally Advanced Breast Cancer |
| NCT03747042 results posted | SCCC-11118; STU-2018-0015 | Ph 2 | completed | Letrozole in Post-Menopausal Patients With Operable Hormone-Sensitive Breast Cancer |
| NCT06016738 OPERA-01 | OP-1250-301 OPERA-01 | Ph 3 | recruiting | OP-1250 (Palazestrant) vs. Standard of Care for the Treatment of ER+/HER2- Advanced Breast Cancer |
| NCT04293393 CARABELA results posted | GEICAM/2019-01 2019-002123-15 | Ph 2 | active not recruiting | Neoadjuvant Study Chemotherapy vs Letrozole + Abemaciclib in HR+/HER2- High/Intermediate Risk Breast Cancer Patients |
| NCT07029399 | NKT5097-101 | Ph 1 | recruiting | A Study With NKT5097 for Adults With Advanced/Metastatic Solid Tumors |
| NCT03006172 | GO39374 2016-003022-17, 2023-508124-36-00 | Ph 1 | active not recruiting | To Evaluate the Safety, Tolerability, and Pharmacokinetics of Inavolisib Single Agent in Participants With Solid Tumors and in Combination With Endocrine and Targeted Therapies in Participants With Breast Cancer |
| NCT02712723 FELINE results posted | CLEE011XUS10T | Ph 2 | active not recruiting | Letrozole Plus Ribociclib or Placebo as Neo-adjuvant Therapy in ER-positive, HER2-negative Early Breast Cancer |
| NCT04931342 BOUQUET | WO42178 GOG-3051, ENGOT-GYN2 | Ph 2 | active not recruiting | A Study Evaluating the Efficacy and Safety of Biomarker-Driven Therapies in Patients With Persistent or Recurrent Rare Epithelial Ovarian Tumors |
Showing 50 of 257 trials
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Pro Key Completed Trials
Completed studies with published results, ranked by significance
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Trial Timeline
Full development history with FDA approval milestones
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Understanding FDA Approval Types
| Count | Type | What it means |
|---|---|---|
| - | ORIG | Original approval - drug first enters market |
| - | SUPPL - Efficacy | New indication (new disease/condition approved) |
| - | SUPPL - Labeling | Label text changes (warnings, dosing updates) |
| - | SUPPL - Manufacturing | Production changes (new facility) |
| - | SUPPL - Chemistry | Formulation changes (new dosage strength) |
Green lines in the timeline show ORIG and Efficacy approvals - the clinically meaningful milestones.
FEMARA FDA Label Details
Indications & Usage
FDA Label (PDF)FEMARA is indicated for the treatment of Breast Cancer.
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Data Sources
Data sourced from official FDA and NIH databases. Click links to verify on original sources.